The present invention relates generally to a peripheral device which is connected to a host machine and, more particularly, to an improved means of connecting and interfacing the peripheral device to the host machine.
Recently, card-type expansion devices like PC cards have been used to connect a peripheral device to a host machine such as a microcomputer in order to expand the functions of the host machine. A card-type expansion device includes a memory card which provides a host machine with a memory function and a communication card which provides the host machine with an interface circuit function. Such card-type expansion devices generally comprise a credit card sized board with functional circuits mounted thereon.
A host machine has a card slot for installing the card-type expansion device. When the connector of the card-type expansion device is connected to the connector of the card slot of the host machine, the card-type expansion device receives drive power from the host machine via the connectors and communicates with the host machine to provide a predetermined function.
In some cases, however, although the connectors match in shape with each other, the physical specifications such as the supply voltage of both the expansion device and the host machine may not match with each other. For instance, a card-type expansion device which is supplied with an operational supply voltage of 3 V cannot be used in a host machine passes an operational supply voltage of 5 V to connected devices. In this respect, each user should check the specifications of a host machine and select a card-type expansion device suitable for use in the host machine.
Accordingly, it is an object of the present invention to provide an improved connection between a host machine and a card device, which does not require the user to check for supply voltage compatibility.